Thank you for the answer. I tried you command but got the following error message:
Afterwards I checked my ffmpeg version:
Unrecognized option 'filter:v'
That is why I tried to install the version from the ppas:
$ ffmpeg -version
ffmpeg version 0.8.4-4:0.8.4-0ubuntu0.12.04.1, Copyright (c) 2000-2012 the Libav developers
There was a warning that because of Ubuntu 12.04 only an older version of ffmpeg could be added by the ppa (I forgot to copy it) and I still get the same error message from ffmpeg while its version seem to not have changed at all.
$ sudo add-apt-repository ppa:jon-severinsson/ffmpeg
$ sudo apt-get update && sudo apt-get upgrade
Furthermore when displaying the version of ffmpeg I can see the following warning:
I need not to stick to ffmpeg if you can tell me how to achieve the same in avconv or transcode or whatever.
*** THIS PROGRAM IS DEPRECATED ***
This program is only provided for compatibility and will be removed in a future release. Please use avconv instead.